Churchland lab

A new paper is out from my lab today in Nature Neuroscience. In this paper, we set out to understand how a single part of the brain can be used to support many behaviors. The posterior parietal cortex, for instance, has been implicated in decision-making, value judgments, attention and action selection. We wondered how that could be: are there categories of specialized neurons that are specialized for each behavior? Or, alternatively, does a single population of neurons multitask to support lots of behaviors? We found the latter possibility to be true. We recorded neurons in rat posterior parietal cortex while rats were making decisions about lights and sounds. We found that neurons could be strongly modulated by the animal’s choice, the modality of the stimulus, or, very often, both of those things. This multitasking did not provide a problem for decoding: a linear combination of responses could easily estimate choice and modality well.

We hope that our observations will change the way people think about how neurons support diverse behaviors because they challenge the prevailing view that neurons are specialized. Horace Barlow (the grandfather of computational neuroscience), argued that neurons in the frog’s retina were specialized for detecting particular kinds of motion. This is likely true in early visual areas, but in higher cortical areas, things are very different. Our observations about multitasking neurons point to a new way of encoding information that, we argue, confers flexibly in how the neurons are used, and could allow their responses to be flexibly combined to support many behaviors. The picture below shows me with co-first authors David Raposo and Matt Kaufman.